Process for encapsulating a water insoluble active

ABSTRACT

A process for encapsulating a water insoluble active including forming a solution by polymerizing one or more hydrophobic monomers and one or more water-soluble acid-containing monomers in the presence of water and one or more water-miscible solvents and one or more neutralizing agents, adding the water insoluble active, and removing the one or more water-miscible solvents from the solution.

This present application is a divisional application of U.S. patentapplication Ser. No. 12/973,084, filed Dec. 20, 2010, now U.S. Pat. No.8,062,758, which is a divisional application of U.S. patent applicationSer. No. 11/035,160, filed Jan. 13, 2005 and now patented as U.S. Pat.No. 7,875,359, each of which is hereby incorporated by reference in itsentirety herein.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention is directed towards copolymers produced bysolution polymerization. More particularly, the present invention isdirected towards self-stabilizing copolymers having opacifyingproperties and processes for producing such polymers.

2. Background Information

Polymers having both hydrophobic and hydrophilic constituents such asstyrene-acrylic acid copolymers are produced by a variety of processesillustrated in the art. In one process commonly referred to as solutionpolymerization, the copolymers are formed by polymerizing thewater-insoluble monomer, e.g., styrene, and the water-soluble monomer,e.g., a carboxylated monomer, in the presence of a water misciblesolvent, neutralizing the acid after the polymerization step hascompleted, and subsequently removing the water-miscible solvent from thesolution. The polymerization step can occur in the presence of acatalyst.

In another variation of this solution polymerization process, thesehydrophobic/hydrophilic type polymers are first polymerized, followed bysimultaneous neutralization and distillation. Other solutionpolymerization processes in the art teach polymerizing at least onehydrophilic monomer and at least one hydrophobic ethylenicallyunsaturated monomer in a non-aqueous solvent, forming an aqueous polymerdispersion from this non-aqueous polymer solution, and subsequentlyadding an aqueous base or acid. While such polymers provide good soilrelease properties and are useful in cleaning compositions, they tendnot to provide opacity to those compositions.

Emulsion polymerization is an example of another process for producinghydrophobic/hydrophilic type polymers. Such processes typically usesurfactants to stabilize the emulsion. For example, processes forproducing alkali-soluble emulsion copolymers of methacrylic acid andwater-insoluble monomers such as styrene are known that utilize anionicand/or nonionic surfactants in an amount sufficient to stabilize theemulsion. Emulsion copolymers can be used as opacifiers in detergent,personal care and other applications. However, they tend not to providegood cleaning benefits in end use application. Consequently, othercleansing polymers are required in detergent formulations that make useof such emulsion copolymers.

Accordingly, there is a need for polymeric ingredients or compounds thatare useful in cleaning compositions while also providing opacity tothose compositions. Further, there is a need for dispersion polymersthat are self-stabilizing.

SUMMARY OF THE INVENTION

The present invention provides a dispersion polymer that isself-stabilizing. For the purpose of the present invention, aself-stabilizing dispersion is defined as one that does not need anysurfactants to stabilize the dispersion, as surfactants can interferewith the ability to formulate these materials. Further, for the purposeof the present application, emulsion polymers are defined as systemswhere surfactants are used to stabilize the dispersion. Like emulsionpolymers, these self-stabilizing dispersion materials can be used asopacifiers in detergent, personal care and other applications. However,unlike emulsion polymers, the dispersion polymers of this inventionprovide good cleaning benefits in end use applications.

Current opacifier technologies utilize high molecular weight emulsionpolymers (i.e., a number average molecular weight (‘Mn’) greater thanabout 100,000 Daltons (‘Da’)) of core-shell type morphology. Incontrast, the polymers according to the present invention are lowmolecular weight solution polymers (i.e., Mn less than about 50,000 Da).They have the additional advantage of providing functionality todetergent formulations, such as dispersancy and anti-redeposition.

Further, the process of the present invention produces extremelyhydrophobic polymers that previously could only be produced by emulsionpolymerization. For the purpose of the present application, “extremelyhydrophobic polymers” refers to those polymers having a water solubilityof less than 1 g/l. Such polymers can be produced from hydrophobicmonomers such as styrene. The process according to the present inventionallows formulation and use of these very hydrophobic copolymers inaqueous systems or formulations. In one aspect, these copolymers can beused as opacifiers in aqueous formulations. Examples of suchhydrophobically modified copolymers include solution polymers of acrylicacid and styrene.

In one aspect according to the process of the present invention, thedispersion copolymer is produced as neutralized materials. This makes iteasier to formulate the dispersion copolymer into formulations that areneutral or alkaline pH, as opposed to traditional emulsion copolymersthat are typically acidic. Such emulsion polymers have to be dilutedbefore formulation, adding another step in the formulation process.

According to the present invention, the above dispersion copolymers aresynthesized by a process wherein the acid monomer is neutralized duringpolymerization. The resulting polymer provides for a self-stabilizingemulsion that maintains its particulate nature even on dilution. Theseparticles can lend opacity to aqueous formulations such as liquiddetergents.

One process according to the present invention for manufacturing thedispersion is as follows. At least one hydrophobic and at least onewater-soluble acid-containing monomer are polymerized in the presence ofwater, one or more water miscible solvents and one or more neutralizingagents. Once polymerized, the water-miscible solvent(s) is removed fromthe solution.

The present invention also discloses a process for encapsulating orcreating microparticulates containing hydrophobic or water-insolubleactives such as perfumes and flavors. This process involves polymerizingat least one hydrophobic monomer and at least one water-solubleacid-containing monomer in the presence of water, one or morewater-miscible solvents and one or more neutralizing agents and thewater insoluble active. The active can be dissolved in a mixture ofwater, one or more water miscible solvents and one or more neutralizingagents. The monomers are then added to the system, with polymerizationoccurring in the presence of the water-insoluble active. Alternatively,the monomers can be polymerized and the water-insoluble active(s) addedat the end of the polymerization process. Particles or particulates areformed during the latter stages of the polymerization process or whenthe water miscible solvent is distilled or stripped off. The activeingredient is then incorporated into these particles.

In one embodiment, the dispersion copolymer is prepared from at leastone hydrophilic acid-containing monomer. This acid-containing monomerincludes, for example, polymerizable carboxylic and/or sulfonicacid-containing monomers. Such monomers can be partially or completelyneutralized at the beginning of or during the polymerization process.

The dispersion copolymer is further prepared from at least onehydrophobic moiety. This hydrophobic moiety can be prepared from atleast one hydrophobic monomer and/or chain transfer agent. Usefulhydrophobic monomers include saturated or unsaturated alkyl, hydroxyalkyl, alkoxyalkyl group, alkoxyaryl, aryl and aryl-alkyl group, alkylsulfonate, aryl sulfonate, siloxane and combinations thereof. Usefulchain transfer agents can have 1 to 24 carbon atoms and includemercaptans, amines, alcohols, α-olefin sulfonates and combinationsthereof.

Accordingly, the present invention provides for a self-stabilizingdispersion copolymer having at least one polymerizable acid-containingmoiety, wherein the at least one acid-containing moiety is at leastpartially neutralized before or during polymerization, and at least onehydrophobic moiety. Examples of useful polymerizable acid-containingmoieties include acrylic acid, methacrylic acid, ethacrylic acid,α-chloro-acrylic acid, α-cyano acrylic acid, methyl-acrylic acid(crotonic acid), α-phenyl acrylic acid, β-acryloxy propionic acid,sorbic acid, α-chloro sorbic acid, angelic acid, cinnamic acid, p-chlorocinnamic acid, β-styryl acrylic acid (1-carboxy-4-phenyl butadiene-1,3),itaconic acid, citraconic acid, mesaconic acid, glutaconic acid,aconitic acid, fumaric acid, tricarboxy ethylene, 2-acryloxypropionicacid, 2-acrylamido-2-methyl propane sulfonic acid, vinyl sulfonic acid,vinyl phosphonic acid, sodium methallyl sulfonate, sulfonated styrene,allyloxybenzene sulfonic acid, maleic acid, maleic anhydride orcombinations thereof. In one aspect, the acid containing moiety isacrylic acid, methacrylic acid, maleic acid, itaconic acid or mixturesthereof.

The hydrophobic moiety can be prepared from at least one hydrophobicmonomer, at least one chain transfer agent or combinations thereof.Examples of useful hydrophobic monomers include styrene, α-methylstyrene, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearylacrylate, behenyl acrylate, 2-ethylhexyl methacrylate, octylmethacrylate, lauryl methacrylate, stearyl methacrylate, behenylmethacrylate, 2-ethylhexyl acrylamide, octyl acrylamide, laurylacrylamide, stearyl acrylamide, behenyl acrylamide, propyl acrylate,butyl acrylate, pentyl acrylate, hexyl acrylate, 1-vinyl naphthalene,2-vinyl naphthalene, 3-methyl styrene, 4-propyl styrene, t-butylstyrene, 4-cyclohexyl styrene, 4-dodecyl styrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl) styrene or combinations thereof. Thehydrophobic monomer can also be siloxane, saturated or unsaturatedalkyl, and alkoxy group, aryl and aryl-alkyl group, alkyl sulfonate,aryl sulfonate or combinations thereof.

When the hydrophobic moiety is prepared from one or more chain transferagents, the chain transfer agent(s) can include 1 to 24 carbon atoms.Further, useful chain transfer agents include mercaptan, amine, alcohol,α-olefin sulfonate or combinations thereof.

The present invention is also directed towards personal careformulations and detergents formulated with the self-stabilizingdispersion copolymer.

The present invention is also directed towards a manufacturing processfor producing the self stabilizing dispersion copolymer. Thismanufacturing process involves at least polymerizing a hydrophobicmoiety and a water-soluble acid-containing monomer in the presence ofone or more water-miscible solvents and one or more neutralizing agents,and removing the one or more water-miscible solvents from the solution.Useful neutralizing agents include NaOH, KOH, Ca(OH)₂, Mg(OH)₂, Zn(OH)₂,ammonia, diethanol amine, monoethanol amine, triethanolamine,morpholine, the lower alkyl amines, lower alkanol amines,2-dimethylaminoethanol, N-methyl morpholine, ethylene diamine orcombinations thereof.

The present invention is also directed towards a process forencapsulating a water insoluble active. This encapsulation processinvolves at least polymerizing one or more hydrophobic monomers and oneor more water-soluble acid-containing monomers in the presence of one ormore water-miscible solvents and one or more neutralizing agents,thereby producing a self-stabilizing solution, adding the waterinsoluble active, and removing the one or more water-miscible solventsfrom the solution. The water insoluble active can be added before orduring the polymerization step. Useful water insoluble actives include.One skilled in the art will readily recognize suitable actives dependingupon end-use application.

DETAILED DESCRIPTION OF THE INVENTION

In one embodiment, the self-stabilizing dispersion copolymer includes apolymer having at least one acid-containing hydrophilic moiety, whereinthe acid-containing moiety is at least partially or even completelyneutralized before or during polymerization, and at least onehydrophobic moiety prepared from at least one hydrophobic monomer and/orchain transfer agent. Useful hydrophobic monomers include siloxanes,saturated or unsaturated alkyls, alkoxy groups, aryl and aryl-alkylgroups, alkyl sulfonates, aryl sulfonates and combinations thereof.Useful chain transfer agents can have 1 to 24 carbon atoms and includemercaptans, amines, alcohols, α-olefin sulfonates and combinationsthereof.

Examples of useful polymerizable acid-containing hydrophilic monomersinclude acrylic acid, methacrylic acid, ethacrylic acid,α-chloro-acrylic acid, α-cyano acrylic acid, β-methyl-acrylic acid(crotonic acid), α-phenyl acrylic acid, β-acryloxy propionic acid,sorbic acid, α-chloro sorbic acid, angelic acid, cinnamic acid, p-chlorocinnamic acid, β-styryl acrylic acid (1-carboxy-4-phenyl butadiene-1,3),itaconic acid, citraconic acid, mesaconic acid, glutaconic acid,aconitic acid, fumaric acid, tricarboxy ethylene, 2-acryloxypropionicacid, 2-acrylamido-2-methyl propane sulfonic acid, vinyl sulfonic acid,vinyl phosphonic acid, sodium methallyl sulfonate, sulfonated styrene,allyloxybenzene sulfonic acid, maleic acid, and maleic anhydride.Combinations of acid-containing hydrophilic monomers can also be used.In one aspect the acid-containing hydrophilic constituent is selectedfrom acrylic acid, methacrylic acid, maleic acid, itaconic acid andmixtures thereof.

According to the process of the present invention, the acid-containingmonomers are neutralized during polymerization. Neutralization agentsinclude, for example, NaOH, KOH, Ca(OH)₂, Mg(OH)₂, Zn(OH)₂, ammonia andamines such as diethanol amine, monoethanol amine, triethanolamine,morpholine, the lower alkyl amines, lower alkanol amines,2-dimethylaminoethanol, N-methyl morpholine, and ethylene diamine.Combinations of neutralization agents can also be used. The choice andlevel of neutralization agent depends on the relative difference insolubility of the acid monomer and the hydrophobic monomer in thewater/water miscible solvent mixture.

Further, the acid moieties can be partially or fully neutralizedaccording to the process of the present invention. The type and degreeof neutralization can affect the solubility difference between themonomers, thus driving the system to form a dispersed particle ratherthan a true solution. For example, polymerization of acrylic acid andstyrene in water and the water miscible solvent isopropanol withoutneutralization during polymerization will produce a water solublepolymer (as exemplified by comparative Example 5 found herein). However,when the acid moiety is neutralized during polymerization, thedispersion copolymer of the present invention is produced. This is dueto the larger difference in solubility of the potassium salt of acrylicacid with styrene as compared to the acrylic acid with styrene. Withoutbeing bound by theory, it is believed that an increase in the differencein solubility produces blocks of acid functional and hydrophobicmonomers in the polymer rather than random copolymers. While the polymerformed is not truly di-block or tri-block, it is blockier than therandom copolymer of traditional solution processes. It is believed thatthis forces the polymer into a dispersed particle.

The solubility difference can also be manipulated by changing the ratioof water to water miscible solvent in the system. Increasing the waterlevel increases the solubility of the neutralized acid monomer anddecreases the solubility of the hydrophobic monomer. Likewise,decreasing the water level decreases the solubility of the neutralizedacid monomer and increases the solubility of the hydrophobic monomer.Manipulation of this solubility difference is key to producing a stabledispersion.

Examples of useful hydrophobic monomers include styrene, α-methylstyrene, 2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearylacrylate, behenyl acrylate, 2-ethylhexyl methacrylate, octylmethacrylate, lauryl methacrylate, stearyl methacrylate, behenylmethacrylate, 2-ethylhexyl acrylamide, octyl acrylamide, laurylacrylamide, stearyl acrylamide, behenyl acrylamide, propyl acrylate,butyl acrylate, pentyl acrylate, hexyl acrylate, 1-vinyl naphthalene,2-vinyl naphthalene, 3-methyl styrene, 4-propyl styrene, t-butylstyrene, 4-cyclohexyl styrene, 4-dodecyl styrene, 2-ethyl-4-benzylstyrene, and 4-(phenylbutyl) styrene. Combinations of hydrophobicmonomers can also be used.

The hydrophobic moieties are selected from siloxanes, aryl sulfonate,saturated and unsaturated alkyl moieties optionally having functionalend groups, wherein the alkyl moieties can have from 5 to 24 carbonatoms. In another aspect, the alkyl moieties can have from 6 to 18carbon atoms. In even another aspect, the alkyl moieties can have from 8to 16 carbon atoms. These alkyl moieties can be optionally bonded to thehydrophilic backbone by means of an alkoxylene or polyalkoxylene linkagesuch as a polyethoxy, polypropoxy or butyloxy (or mixtures thereof)linkage having from 1 to 50 alkoxylene groups. Alternatively, thehydrophobic moiety can be composed of relatively hydrophobic alkoxygroups such as butylene oxide and/or propylene oxide in the absence ofalkyl or alkenyl groups.

Alternatively, or in addition to, the hydrophobic moiety can beintroduced into the dispersion copolymer in the form of a chain transferagent. In one embodiment the chain transfer agent has from 1 to 24carbon atoms. In another embodiment the chain transfer agent has from 1to 14 carbon atoms. In even another embodiment the chain transfer agenthas from 3 to 12 carbon atoms. The chain transfer agent can be selectedfrom mercaptans or thiols, amines, alcohols, or α-olefin sulfonates. Acombination of chain transfer agents can also be used.

Mercaptans useful in this invention include organic mercaptans having atleast one —SH or thiol group and which are classified as aliphatic,cycloaliphatic, or aromatic mercaptans. The mercaptans can contain othersubstituents in addition to hydrocarbon groups. Such substituentsinclude carboxylic acid groups, hydroxyl groups, ether groups, estergroups, sulfide groups, amine groups and amide groups. Suitablemercaptans include, for example, methyl mercaptan, ethyl mercaptan,butyl mercaptan, mercaptoethanol, mercaptopropanol, mercaptobutanol,mercaptoacetic acid, mercaptopropionic acid, thiomalic acid, benzylmercaptan, phenyl mercaptan, cyclohexyl mercaptan, 1-thioglycerol,2,2′-dimercaptodiethyl ether, 2,2′-dimercaptodipropyl ether,2,2′-dimercaptodiisopropyl ether, 3,3′-dimercaptodipropyl ether,2,2′-dimercaptodiethyl sulfide, 3,3′-dimercaptodipropyl sulfide,bis(β-mercaptoethoxy)methane, bis(β-mercaptoethylthio)methaneethanedithio-1,2, propanedithiol-1,2,butanedithiol-1,4,3,4-dimercaptobutanol-1, trimethylolethanetri(3-mercaptopropionate), pentaerythritol tetra(3-mercapto-propionate),trimethylolpropane trithioglycolate, pentaerythritoltetrathio-glycolate, octanethiol, decanethiol, dodecanethiol, andoctadecylthiol. In one aspect the mercaptan chain transfer agentincludes 3-mercaptopropionic acid and dodecanethiol.

Suitable amines useful as chain transfer agents include, for example,methylamine, ethylamine, isopropylamine, n-butylamine, n-propylamine,iso-butylamine, t-butylamine, pentylamine, hexylamine, benzylamine,octylamine, decylamine, dodecylamine, and octadecylamine. In one aspectthe amine chain transfer agent includes isopropyl amine and docylamine.

Suitable alcohols useful as chain transfer agents include, for example,methanol, ethanol, isopropanol, n-butanol, n-propanol, iso-butanol,t-butanol, pentanol, hexanol, benzyl alcohol, octanol, decanol,dodecanol, and octadecanol. In one aspect the alcohol chain transferagent includes isopropanol and dodecanol.

Other hydrophobic monomers that can be used to produce the dispersioncopolymer include α-olefin sulfonates such as the C₈-C₁₈ α-olefinsulfonates commercially available as Bioterge AS40 (Stepan Company,Northfield, Ill.), Hostapur OS liquid (Clariant International Ltd.,Muttenz, Switzerland), and Witconate AOS (Crompton Corporation,Middlebury, Conn.).

In one aspect the water-miscible solvent is capable of forming anazeotrope with water. Examples of solvents useful in the presentinvention include alcohols such as methanol, ethanol, and isopropylalcohol; glycol ethers; and acetone. If the solvent is a low boilingsolvent such as an alcohol or acetone, it can be stripped from thesolution.

The present invention also discloses a process for encapsulating orcreating microparticulates containing hydrophobic or water-insolubleactives such as perfumes and flavors. This process involves polymerizingat least one hydrophobic monomer and at least one water-solubleacid-containing monomer in the presence of water, one or morewater-miscible solvents and one or more neutralizing agents and thewater insoluble active. The active can be dissolved in a mixture ofwater, one or more water miscible solvents and one or more neutralizingagents. The monomers are then added to the system, with polymerizationoccurring in the presence of the water-insoluble active. Alternatively,the monomers can be polymerized and the water-insoluble active(s) addedat the end of the polymerization process. Particles or particulates areformed during the latter stages of the polymerization process or whenthe water miscible solvent is distilled or stripped off. The activeingredient is then incorporated into these particles.

As an example, one application of the present process involvesencapsulation of laundry detergent and automatic dishwasher activeingredients. These encapsulated active ingredients can include rinseaids, fragrances, anti-wrinkling aids, one or more surfactants,builders, ion exchangers, alkalis, anticorrosion materials,anti-redeposition materials, optical brighteners, fragrances, dyes,chelating agents, enzymes, whiteners, brighteners, antistatic agents,sudsing control agents, solvents, hydrotropes, bleaching agents,perfumes, bleach precursors, water, buffering agents, soil removalagents, soil release agents, softening agents, silicones, enzymes, inertdiluents, buffering agents, corrosion inhibitors, graying inhibitors,stabilizers or combinations thereof.

The process for encapsulation according to the present invention is alsouseful in many other applications requiring a protective coating. Forexample, the process can be used as a coating for pills. Such coatingscan be formulated so that they do not dissolve in the mouth, but insteaddissolve elsewhere in the gastro-intestinal tract, thereby enabling acontrolled release of the active material. Likewise, cleaning activescould be encapsulated and released in a controlled manner in a toiletbowl. Nutrients and/or weed killers can be encapsulated for controlledrelease in agricultural applications. The process can encapsulateorganic liquids such as fragrances for release under a given set ofconditions. These encapsulated fragrances can be used in a variety ofapplications, e.g., kitty litter, diapers and feminine care products,etc. One of skill in the art will recognize many other applications forwhich these polymers are useful as protective coatings.

The encapsulation process according to the present invention is usefulfor encapsulating materials in a liquid detergent where solid materialsare suspended in the liquid detergent. The coating can be insoluble dueto ionic strength, high surfactant concentration, and/or high pH of theliquid detergent. The coating can be designed to disintegrate, forexample, either as the liquid detergent is diluted in the wash water orlater in the rinse cycle. Shampoo, body wash and other personal careproducts can also be formulated containing actives encapsulated usingthis process.

Microcapsules containing active ingredients can be formulated intoliquid detergents for laundry or dishwash applications, as well asshampoo and bodywash applications. In one aspect, the encapsulatedactive ingredient(s) would be protected from reacting with otheringredients in the detergent, shampoo, or bodywash in formulation, andreleased when diluted in-use. For example, this can be useful in ashampoo/conditioner having a conditioner encapsulated by the process ofthe present invention where the conditioner is not be released until theshampoo is diluted, thus allowing the conditioner to work on the hairafter shampooing.

The microcapsules of encapsulated actives or actives adsorbed onto inertsolids can be made large enough to be visible, adding an attractivevisual effect of suspended capsules in a personal case formulation. Oneskilled in the art will recognize that the encapsulated materials ofthis invention can be used in other applications such as watertreatment, oil field, paper coating, and pharmaceuticals.

POLYMER EXAMPLES Example 1

An initial charge of 534 g of deionized water and 486 g of isopropylalcohol as cosolvent, 326 g of 45% KOH solution as neutralizer, and0.147 grams of ferrous ammonium sulfate hexahydrate were added to a2-liter glass reactor. The reactor contents were heated to reflux(approximately 84° C.).

At reflux, a monomer solution of 188 g of acrylic acid and 272 g ofstyrene were continuously added to the reactor over a 3.5 hour period.The following initiator solution was added at the same time as themonomer solution, but over a 4 hour period instead.

Initiator solution Sodium persulfate 20 g Water 83 g Hydrogen peroxide35% 58.2 g  

After adding the monomer and initiator solutions, the reactiontemperature was then maintained at about 84° C. for one hour. 7.4 gramsof erythrobic acid dissolved in 29 grams of water was added over this 1hour period. 7.4 grams of t-butyl hydroperoxide (70% solution in water)dissolved in 29 grams of water was also added over the same 1 hourperiod. Both the erythrobic acid and the t-butyl hydroperoxide serve inconsuming any residual monomer that may be left unreacted. The reactionwas then held at 84° C. for an additional hour. The alcohol cosolventwas removed from the polymer solution by azeotropic distillation undervacuum. During distillation, 230 grams of deionized water was added tothe polymer solution. A small amount of ANTIFOAM 1400 (0.10 g) (100%active silicone fluid, Dow Corning, Midland, Mich.) was added tosuppress any foam generated during distillation. Approximately 780 g ofwater and isopropyl alcohol were distilled off. The final solution wasan opaque white milky dispersion.

Example 1A

Stability Testing

TABLE 1 Stability Comparison Polymer Aging test Result Example 1 1 yearat room Stable, no temperature phase separation Example 1 1 freeze thawcycle Stable, no phase separation Commercial styrene-acrylic 1 freezethaw cycle Unstable, phase emulsion copolymer separation (Acusol ™ OP301, available from Rohm and Haas, Philadelphia, PA)

Example 2

An initial charge of 174 g of deionized water, 159 g of isopropylalcohol, 63.6 g of 45% KOH solution and 0.0478 grams of ferrous ammoniumsulfate hexahydrate were added to a 3 liter glass reactor. The reactorcontents were heated to reflux (approximately 84° C.).

At reflux, a monomer solution of 36.7 g of acrylic acid and 124 g ofstyrene was continuously added to the reactor over a 3.5 hour period.The following initiator solution was added at the same time as themonomer solution, but over a 4 hour period.

Initiator solution Sodium persulfate 6.5 g Water  27 g Hydrogen peroxide35% 19.0 g 

After adding the monomer and initiator solutions, the reactiontemperature was then maintained at about 84° C. for one hour. 1.2 gramsof erythrobic acid dissolved in 10 grams of water was added over this1-hour period. 1.2 grams of t-butyl hydroperoxide (70% solution inwater) dissolved in 10 grams of water was also added over this same1-hour period. The reaction was then held at 84° C. for an additionalhour. The alcohol cosolvent was removed from the polymer solution byazeotropic distillation under vacuum. During distillation, 60 grams ofdeionized water was added to the polymer solution. A small amount ofANTIFOAM 1400 (0.10 g) was added to suppress any foam generated duringdistillation. Approximately 240 g of water and isopropyl alcohol weredistilled off. The final solution was an opaque white milky dispersion.

Example 3

An initial charge of 534 g of deionized water, 486 g of isopropylalcohol, 272 g of 45% KOH solution and 0.147 grams of ferrous ammoniumsulfate hexahydrate were added to a 3 liter glass reactor. The reactorcontents were heated to reflux (approximately 84° C.).

At reflux, a monomer solution of 188 g of methacrylic acid and 151 g ofstyrene were continuously added over a period of 3.5 hours. Thefollowing initiator solution was added at the same time as the monomersolution, but over a period of 4 hours.

Initiator solution Sodium persulfate 20 g Water 83 g Hydrogen peroxide35% 58.2 g  

After adding the monomer and initiator solutions, the reactiontemperature was maintained at about 84° C. for one hour. 7.4 grams oferythrobic acid dissolved in 29 grams of water was added over this1-hour period. 7.4 grams of t-butyl hydroperoxide (70% solution inwater) dissolved in 29 grams of water was also added over the same1-hour period. The reaction was then held at 84° C. for an additionalhour. The alcohol cosolvent was removed from the polymer solution byazeotropic distillation under vacuum. During distillation, 230 grams ofdeionized water was added to the polymer solution. A small amount ofANTIFOAM 1400 (0.10 g) was added to suppress any foam generated duringdistillation. Approximately 780 g of water and isopropyl alcohol weredistilled off. The final solution was an opaque white milky dispersion.

Example 4

An initial charge of 150 g of deionized water, 264 g of isopropylalcohol and 0.0799 grams of ferrous ammonium sulfate hexahydrate wereadded to a 2 liter glass reactor. The reactor contents were heated toreflux (approximately 84° C.).

At reflux, a monomer solution of 102 g of acrylic acid and 147.6 g ofstyrene was added over a 3 hour period. The following initiator, causticand chain transfer solutions were added at the same time as the monomersolution, but over a period of 3.5, 3 and 2.5 hours, respectively.

Initiator solution Sodium persulfate 20 g Water 83 g Hydrogen peroxide35% 58.2 g Caustic solution 50% NaOH 119 g Deionized water 119 g Chaintransfer solution 3-mercapto propionic acid 9.3 g Deionized water 44 g

After adding the monomer, initiator, chain transfer and causticsolutions, the reaction temperature was maintained at about 84° C. forone hour. 2 grams of erythrobic acid dissolved in 15 grams of water wasadded over a 30-minute period. 2 grams of t-butyl hydroperoxide (70%solution in water) dissolved in 15 grams of water was added over thesame 30-minute period. The reaction was then held at 84° C. for anadditional hour. The alcohol cosolvent was removed from the polymersolution by azeotropic distillation under vacuum. During distillation,450 grams of deionized water was added to the polymer solution. A smallamount of ANTIFOAM 1400 (0.10 g) was added to suppress any foamgenerated during distillation. Approximately 290 g of water andisopropyl alcohol were distilled off. The final solution was an opaquewhite milky dispersion.

Example 5 Comparative Example of a Solution Polymer Synthesized byAddition of a Neutralization Agent During Distillation as Described inU.S. Pat. No. 5,650,473

An initial charge of 150 g of deionized water, 264 g of isopropylalcohol (cosolvent) and 0.0799 grams of ferrous ammonium sulfatehexahydrate were added to a 2 liter glass reactor. The reactor contentswere then heated to reflux (approximately 84° C.).

At reflux, a monomer solution of 102 g of acrylic acid and 147.6 g ofstyrene was continuously added over a 3 hour period. The followinginitiator and chain transfer solutions were added at the same time asthe monomer solution, but over a period of 3.5 and 2.5 hours,respectively.

Initiator solution Sodium persulfate 20 g Water 83 g Hydrogen peroxide35% 58.2 g   Chain transfer solution 3-mercapto propionic acid 9.3 g  DIwater 44 g

After addition of the monomer, initiator and chain transfer solutions,the reaction temperature was maintained at about 84° C. for one hour. 2grams of erythrobic acid dissolved in 15 grams of water was added over30 minutes. Over the same 30-minute time period, 2 grams of t-butylhydroperoxide (70% solution in water) dissolved in 15 grams of waterwere added. The reaction was then held at 84° C. for an additional hour.The alcohol cosolvent was removed from the polymer solution byazeotropic distillation under vacuum. A solution of 119 grams of 50%NaOH dissolved in 119 grams of deionized water was added during thedistillation. A small amount of ANTIFOAM 1400 (0.10 g) was added tosuppress any foam generated during distillation. Approximately 290 g ofwater and isopropyl alcohol were distilled off. The final solution was aclear yellow to amber solution.

COMPARATIVE EXAMPLES Example 6

The opacifying properties of the polymer of Example 1 was compared tothat of a comparative polymer produced by the process described in U.S.Pat. No. 5,650,473 for making styrene copolymers and as detailed inExample 5. The results are provided below in Table 2.

TABLE 2 Opacity Results Wt % active Opacity of the Particle size of thepolymer in commercial bleach polymer solution as commercial solutionwith measured by light Polymer bleach polymer scattering (nm) Example 10.05 Opaque white 300 to 500 solution Comparative polymer 0.05 Noopacity No particles detected of Example 5 Commercial styrene- 0.05Opaque white 600 to 800 acrylic emulsion solution copolymer (Acusol ™ OP301 available from Rohm and Haas, Philadelphia, PA)

The above data indicates that polymers according to this invention(here, the polymer of Example 1), when synthesized by a process thatincludes pre-neutralization, are excellent pacifiers and compare wellwith the performance of a commercial opacifier. However, the comparativepolymer made by post-neutralization does not have opacifying propertiesbecause it is a true solution. This is explained by the particle sizedata. The polymer of Example 1 is in the formed of dispersed particleswhereas the comparative polymer of Example 5 is in the form a truesolution.

Further, the commercial opacifier is a 40% solution that has to bediluted to a 10% solution before it can be added to a formulation. Theopacifiers of this invention do not have to prediluted and can be usedas a 40% solution, making it easier to formulate.

Example 7

Soil Anti-Redeposition

The polymer of Example 1 was tested for anti-redeposition properties ina commercial liquid detergent (Wisk) formulation. The test was conductedin a full scale washing machine using 3 cotton and 3 polyester/cottonswatches. The soil used was 17.5 g rose clay, 17.5 g bandy black clay (astandard clay used in detergency testing) and 6.9 g oil blend (75:25vegetable/mineral). The test was conducted over 3 cycles using 118 g ofcommercial liquid laundry detergent per wash load. The polymer ofExample 1 was dosed as detailed in the Table. Wash conditions weretemperature of 34° C. (93° F.), 150 ppm hardness and a 10-minute washcycle.

TABLE 3 Change in Color (ΔE) ΔE Sample Cotton Polyester/cottonCommercial detergent 1.63 0.72 0.1% Example 1 0.42 0.22 0.1% commercialopacifier 1.7 0.8 (Acusol ™ OP 301 available from Rohm and Haas,Philadelphia, PA)The color indices L (white to black) a (red to green) and b (blue toyellow) of the test swatches were measured before and after the 3 washcycles. L, a and b values before the first wash cycle and after thethird cycle were measured as L₁, a₁, b₁ and L₂, a₂, b₂, respectively,using a spectrophotometer. The change in ‘color’ (‘ΔE’) was thencalculated using the following equation—ΔE=[(L ₁ −L ₂)²+(a ₁ −a ₂)²+(b ₁ −b ₂)²]^(0.5)ΔE is a measure of how clean the test swatches are after the 3 washcycles. The lower the ΔE value, the less of a change from the originalswatch color. Accordingly, a smaller ΔE means better cleaning. The dataindicates that small amounts of polymer according to the presentinvention provide commercial detergent formulations with excellentanti-redeposition properties (the smaller the ΔE, the better theanti-redeposition property). In contrast, the commercial opacifierproduced by emulsion polymerization does not provide anyanti-redeposition properties.

Example 8 Opacity Evaluation

Dilutions of Polymer 1 were prepared with deionized water for evaluationon a Hach Turbidimeter. A commercial liquid laundry detergent sample(Wisk) was run to determine the level of turbidity that their currentproduct provides. (It should be noted that the commercial product alsocontains blue dye.)

TABLE 4 Opacity Evaluation Example 1 Polymer Weight % NTUs 0.01 191 0.02354 0.04 628 0.06 868 0.08 1087 0.10 1298 Commercial Detergent 260sample with opacifierThe data indicate that a small amount of opacifier according to thepresent invention (0.01 to 0.02 weight percent of formulation) providessimilar opacity to that of commercial formulations.

Example 9 Calcium Binding Capacity

The calcium binding capacity of polymer was determined through the EDTAtitration procedure. The data indicate that the calcium binding ofpolymers of this invention are similar to that of the conventionalsolution polymers. However, as seen in Example 6, the conventionalsolution polymer does not provide opacifying properties. Furthermore,the calcium binding is far superior to commercial opacifier materials.

TABLE 5 Calcium Binding Capacity Sample CBC Example 1 148.9 Comparativepolymer of Example 5 142.4 Commercial opacifier of Example 6 0

Example 10 Encapsulation of a Water Insoluble Additive or Active

An initial charge of 174 g of deionized water and 158 g of isopropylalcohol as the solvent, 105 g of 45% KOH solution as the neutralizer,23.6 grams of orange oil (water insoluble active) and 0.04794 grams offerrous ammonium sulfate hexahydrate were added to a 2 liter glassreactor. The reactor contents were heated to reflux (approximately 84°C.).

Once at reflux, continuous additions of 61 g of acrylic acid monomer and89 g of styrene monomer were added over a 3-hour period. The followinginitiator solution was added at the same time as this monomer solutionbut over a total time of 3.5 hours.

Initiator solution Sodium persulfate 6.5 g  Water 27 g Hydrogen peroxide35% 19 g

After adding all of the monomer and initiator solutions, the reactiontemperature was maintained at about 84° C. for one hour. 2.4 grams oferythrobic acid dissolved in 29 grams of water was added over 1 hour. Atthe same time, 2.4 grams of t-butyl hydroperoxide (70% solution inwater) dissolved in 29 grams of water was added over this 1-hour period.The reaction was then held at 84° C. for an additional hour. The alcoholcosolvent was removed from the polymer solution by azeotropicdistillation under vacuum. During the distillation, 60 grams ofdeionized water was added to the polymer solution. A small amount ofANTIFOAM 1400 (0.10 g) was added to suppress any foam generated duringdistillation. Approximately 240 g of water and isopropyl alcohol weredistilled off. The final solution was an opaque white milky dispersion.

Example 11

An initial charge of 180 g of deionized water and 180 g of isopropylalcohol were added to a 2 liter glass reactor. The reactor contents wereheated to reflux (approximately 83° C.).

At reflux, 96 g of acrylic acid and 85 g of lauryl methacrylate wereadded continuously over a period of 1.5 hours. 107 g of NaOH was alsoadded at the same time the monomers were over that 1.5 hour period. Thefollowing initiator solution was added at the same time as the monomersolution, but over a period of 2 hours instead of 1.5 hours.

Initiator solution Sodium persulfate 16 g Water 80 g

After adding all of the monomers (acrylic acid and lauryl methacrylate),caustic (NaOH) and initiator solution, the reaction temperature wasmaintained at about 83° C. for one hour. The alcohol cosolvent wasremoved from the polymer solution by azeotropic distillation underatmospheric pressure. During distillation 80 grams of deionized waterwas added to the polymer solution. A small amount of ANTIFOAM 1400 (0.10g) was also added to suppress any foam generated during distillation.Approximately 252 g of a mixture of water and isopropyl alcohol weredistilled off. The final solution was an opaque white milky dispersion.

Example 12

Dilutions of Polymer 11 were prepared with DI water for evaluation on aHach Turbidimeter. A commercial liquid laundry detergent sample (Wisk)was run to determine the level of turbidity that this commercial productprovides. (It should be noted that the commercial product contains bluedye.)

TABLE 6 Opacity Evaluation Wt % Polymer of Example 11 NTUs 0.050 95.50.075 147 0.100 213 0.125 294 0.150 384 0.175 509 0.200 637 CommercialDetergent 260 sample with opacifierThe data indicates that small amounts of opacifier according to thepresent invention (here, 0.100 to 0.125 weight % of formulation) willprovide similar opacity to that of commercial formulations.

PRODUCT FORMULATION EXAMPLES Example 13 Personal Care formulationsShampoo Formulation

Ingredients Weight % Lauryl ether sulfate 2 EO 16.0 Cocamidopropylbetaine 2.0 Deposition polymer 0.1 Dimethiconol polymer emulsion (60%)3.2 Polymer of Example 1 0.1 Water Balance

Water Repellant Sunscreen

Ingredients Weight % Glycerin 5.0 Polymer of Example 4 2.0 PEG 100stearate 5.0 Isostearyl stearate 4.0 Octyl methoxycinnamate 7.5 Butylmethoxydibenzoylmethane 1.5 Hexyl methicone 5.0 DI water balance

Example 14 Liquid Detergent Formulation

Ingredient Weight % DI Water 34.25 Sodium Citrate 9.0 Propylene Glycol8.0 Sodium xylene sulfonate (40%) 18.75 Bio-Soft D-40 (sodiumalkylbenzene sulfonate, 20.00 linear, Stepan Company, Northfield,Illinois) Neodol 25-9 (C₁₂-C₁₅ alcohol ethoxylate, 9 7.0 moles EO permole alcohol, Shell Chemicals, Houston, Texas) Polymer of Example 1 0.10Water, fragrance, colorants balance

Example 15 Hard Surface Cleaning Formulations Acid Cleaner

Ingredient Weight % Citric acid (50% solution) 12.0 C12-15 linearalcohol ethoxylate with 3 moles of EO 5.0 Alkylbenzene sulfonic acid 3.0Polymer of Example 2 0.2 Water

Alkaline Cleaner

Ingredient Weight % Water 89.0 Sodium tripolyphosphate 2.0 Sodiumsilicate 1.9 NaOH (50%) 0.1 Dipropylene glycol monomethyl ether 5.0Octyl polyethoxyethanol, 12-13 moles EO 1.0 Polymer of example 3 0.1

Example 16 Automatic Dishwash Formulation

Ingredients Weight % Sodium tripolyphosphate 25.0 Sodium carbonate 25.0C₁₂-C₁₅ linear alcohol ethoxylate with 7 moles of EO 1.0 Polymer ofExample 3 1.0 Sodium sulfate balance

Example 17 Floor Polish

Ingredients Weight % Syncrowax HGL 4.0 Crosterene 2.7 Silicone fluid(500 cs) 3.0 DI water 89.0 Polymer of Example 4 5.0

Example 18 Liquid Hand Soap

Ingredient Weight % Distilled palm kernel fatty acids 9.0 Tallow fattyacids 3.0 Crodalan LA 1010 (cetyl acetate (and) acetylated 1.5 lanolinalcohol, Croda, Yorkshire, England) Na Lauryl sulfate 6.0 Morpholine 5.0Polymer of Example 2 0.5 Water Balance

Example 19 Paper Coating composition

Ingredient Weight % Predispersed clay 15 Precipitated calcium carbonate15 Ground calcium carbonate 15 Sodium polyacrylates as dispersing agent0.2 Oxidized starch 5 Styrene-butadiene latex 12 Polymer of Example 1 asopacifier 0.5 Water Balance

Although the present invention has been described and illustrated indetail, it is to be understood that the same is by way of illustrationand example only, and is not to be taken as a limitation. The spirit andscope of the present invention are to be limited only by the terms ofany claims presented hereafter.

1. A process for encapsulating a water insoluble active comprising thesteps of: forming a solution by polymerizing one or more hydrophobicmonomers and one or more water-soluble acid-containing monomers in thepresence of one or more water-miscible solvents and one or moreneutralizing agents, adding the water insoluble active, and removing theone or more water-miscible solvents from the solution, wherein the oneor more acid-containing monomers is at least partially neutralizedbefore or during polymerization.
 2. The process according to claim 1wherein the water insoluble active is added before or during thepolymerization step.
 3. The process according to claim 1 wherein thewater insoluble active is rinse aids, fragrances, anti-wrinkling aids,one or more surfactants, builders, ion exchangers, alkalis,anticorrosion materials, anti-redeposition materials, opticalbrighteners, fragrances, dyes, chelating agents, enzymes, whiteners,brighteners, antistatic agents, sudsing control agents, solvents,hydrotropes, bleaching agents, perfumes, bleach precursors, water,buffering agents, soil removal agents, soil release agents, softeningagents, silicones, enzymes, inert diluents, buffering agents, corrosioninhibitors, graying inhibitors, stabilizers and combinations thereof. 4.The process of claim 1 wherein the one or more acid-containing monomersis selected from the group consisting of acrylic acid, methacrylic acid,ethacrylic acid, α-chloro-acrylic acid, α-cyano acrylic acid,β-methyl-acrylic acid (crotonic acid), α-phenyl acrylic acid, β-acryloxypropionic acid, sorbic acid, α-chloro sorbic acid, angelic acid,cinnamic acid, p-chloro cinnamic acid, β-styryl acrylic acid(I-carboxy-4-phenyl butadiene-1,3), itaconic acid, citraconic acid,mesaconic acid, glutaconic acid, aconitic acid, fumaric acid, tricarboxyethylene, 2-acryloxypropionic acid, 2-acrylamido-2-methyl propanesulfonic acid, vinyl sulfonic acid, vinyl phosphonic acid, sodiummethallyl sulfonate, sulfonated styrene, allyloxybenzene sulfonic acid,maleic acid, maleic anhydride and combinations thereof.
 5. The processof claim 4 wherein the one or more acid-containing monomers is acrylicacid, methacrylic acid, maleic acid, itaconic acid or mixtures thereof.6. The process of claim 1 wherein the one or more hydrophobic monomersis selected from the group consisting of styrene, a-methyl styrene,2-ethylhexyl acrylate, octyl acrylate, lauryl acrylate, stearylacrylate, behenyl acrylate, 2-ethylhexyl methacrylate, octylmethacrylate, lauryl methacrylate, stearyl methacrylate, behenylmethacrylate, 2-ethylhexyl acrylamide, octyl acrylamide, laurylacrylamide, stearyl acrylamide, behenyl acrylamide, propyl acrylate,butyl acrylate, pentyl acrylate, hexyl acrylate,1-vinyl naphthalene,2-vinyl naphthalene, 3-methyl styrene, 4-propyl styrene, t-butylstyrene, 4-cyclohexyl styrene, 4-dodecyl styrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl) styrene and combinations thereof.
 7. Theprocess of claim 1 wherein the one or more hydrophobic monomers isselected from the group consisting of siloxane, saturated or unsaturatedalkyl, and alkoxy group, aryl and aryl-alkyl group, alkyl sulfonate,aryl sulfonate and combinations thereof.
 8. The process of claim 1wherein the one or more neutralizing agents is selected from the groupconsisting of NaOH, KOH, Ca(OH)2, Mg(OH)2, Zn(OH)2, ammonia and aminesand mixtures thereof.
 9. The process of claim 8 wherein the one or moreneutralizing agents is an amine selected from the group consisting ofdiethanol amine, monoethanol amine, triethanolamine, morpholine, loweralkyl amines, lower alkanol amines, 2 dimethylaminoethanol, N-methylmorpholine ethylene diamine and mixtures thereof.
 10. The process ofclaim 1 wherein the one or more water-miscible solvents is selected fromthe group consisting of alcohols, glycol ethers, and acetone andcombinations thereof.
 11. The process of claim 10 wherein the one ormore water-miscible solvents is an alcohol selected from the groupconsisting of methanol, ethanol and isopropyl alcohol and combinationsthereof.
 12. The process of claim 3 wherein the water insoluble activeis a perfume, dye or a fragrance.